A sensitive immunoassay for the detection of bacterial contamination of platelets is proposed for development under this Phase I grant. No commercial assay of this type is currently available. However, transfusion-associated sepsis resulting from the use of contaminated platelets is estimated to cause over 20 fatalities per year in the United States, the majority due to gram-negative bacteria. The frequency of non- fatal cases of clinical sepsis is 10-100 times greater. Recent studies have shown that about 1 in 3,000 platelet units is contaminated with bacteria. Because of the potential for such contamination, the FDA has established a five day expiration date for platelet units stored at room temperature. As a result, about 15% of platelet units are discarded every week. The proposed immunoassay will rely on the capture and detection of bacterial lipopolysaccharides (LPS), with emphasis on the selection of reagents with broad specificity for gram-negative bacterial species. The assay will combine the affinity of anti-LPS antibodies or LPS-binding peptides with immunofiltration and electrochemical detection, approaches which have been demonstrated to significantly enhance the sensitivity of detection of bacteria. The aim is to develop a cost-effective, technically robust assay capable of automation within the blood bank or hospital environment. PROPOSED COMMERCIAL APPLICATIONS: Approximately 5-8 million platelet units are generated each year in the United States, none of which are currently screened for bacterial contamination due to lack of an available commercial assay. The proposed assay will be the first to address this urgent need. The technically simple, relatively inexpensive assay to be developed will ultimately be made available in automated format to every blood bank and hospital in the United States, a significant market estimated to be over $100 million per year.